Light-projecting apparatus.



F. A. HARDYMAN.

LIGHT PROJECTING APPARATUS.

APPLICATION FILED SEPT-7.1815.

1 204,272. Patented Nov. 7, 1916.

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UNITED STATES PATENT orrrcn.

FRANK A. HABIDY MAN, OF QUINCY ILLINOIS, ASSIGNOR TO AUTOMATIC GAS POWERCOMPANY, OF QUINCY, ILLINOIS, A CORPORATION 033 SOUTH DAKOTA.

LIGHT-IPROJECTING APPARATUS.

Specification of Letters Patent.

Patented Nov. '7, 1916.

T0 at? whom it may concern:

Be it brown that I, FRANK A. HARDYMAN, a citizen of the United States,and a resident of Quincy, in the county of Adams and State of Illinois,have invented certain new and useful improvements in Light- ProjectingApparatus; and I do hereby declare that the following is a full, clear,and exact description thereof, reference being had to the accompanyingdrawings, and to the letters of reference marked thereon, which form apart of this specification.

This invention relates to a light projecting apparatus forcinematographs and picture projecting machines.

Most cinematographs or moving picture projecting machines now in generaluse employ as the source of light electric arc-lights. The are lightsused are either alternating current or direct current ones, depending ofcourse upon-whether an alternating or a direct current is supplied tothe hghtmg system in the locality in which the picture projectingmachine is used. With an alternating are as thesourcc of light, thellght stream is not a steady and unva'rymg one, but varies in intensitydue to the fluctuation of the alternating current supplied thereto. Onthe other hand, while a direct current are gives a more steady lightstream, yet the same varies somewhat in its intensity due to the factthat the impurities in the carbons interfere with the combustion. Ineither case, arc lights are costly to install and eX- pensive in theirmaintenance, and further, require extreme care in operatmg because ofthe intense heat developed and also due to the fact that the light flamewhich is caused by combustion is for all intents and purposes exposedand unprotected.

Among the objects of my invent on is to provide a light projectingapparatus for picture projecting machines of kind referred to, wherebyan incandescent electric lamp of the bulb type may be successfully usedas the source of light.

A further object of my invention is to provide a light projectingapparatus for the purpose stated that will be portable and also bedevoid of lenses.

A still further object of my inventlon is to provide a light projectingapparatus wherein the reflector used has such a curvature that thereflected light rays Wlll be converged toward the principal axis of thereand concentrated on one of the proectmg lenses of the pictureprojecting machine with which my apparatus is used.

The invention consists further in the matters hereinafter described andmore particularly pointed out in the appended claim.

In the accompanying drawings: Figure 1 is a longitudinal sectional viewof a light projecting apparatus constructed in accordance with myinvention, and showing the projecting lenses and picture projectingmachine of the type with which my improved apparatus isused; Fig. 2 is atransverse sectional view taken on line 22 of Fig. 1; and Fig. 3 is alongitudinal sectional view with parts in elevation of a detail ofconstruction to be hereinafter described.

Referring to the drawings, illustrating in detail a light projectingapparatus embodying the features of my invention, 10 indicates what mayfor convenience be termed a lamp house. Said lamp house, comprises atubular body portion 11, which as shown in the drawings is cylindricalin cross-section, and open at both of its ends. To one end of said bodyportion 11, namely its front end, is secured a tubular member 12, whichas shown is frusto-conical in shape. The outer end of said member 12 isprovided with av centrally disposed opening 13, through which the raysof light from the source contained in the lamp house are emitted andpass through the moving film or picture slide placed in front of theopening 13 in the said lamp house. The inner end of said hood 12 issecured to the front end of said body portion 11. As illustrated in Fig.1, said parts are secured together by an annular flange 15 clenched overan annular flange 16 on said body portion 11. The other end of the bodyportion 11 is closed by a reflector device 17 the same comprising anannular member 18 adapted to be inserted in the open end of said bodyportion. A back plate 19 is secured to said annular member 18 by .aflange 20 on said back plate being clenched over a flange 21 on saidpart 18. As shown in Fig. 1, said flanges 20, 21 project beyond the bodyportion 11 and serve to contact with the end of the body portion andprevent the reflector device 17 from being forced too far into the lamphouse. Set within the annular member 18 is a concave reflector 22. 'Asshown the base of said concave reflector 22 bears against the innersurface of said back plate 19 at the center thereof. The outer edge ofsaid reflector 22 is provided with an annular flange 23 which bearsoutward against an annular marginal flange 24 on the inner edge of saidmember 18. Both the concave reflector 22 and the back plate 19 areprovided in their contacting parts with centrally disposed registeringholes or openings. Inserted in such holes is a sleeve 25. Said sleeve 25extends outward for a short distance to the rear of the back plate 19and the inner end of the sleeve is flush or substantially so with thereflecting surface of the reflector 22. Said sleeve 25 is secured in theopening in the back plate 19 in any desired manner. All of the parts ofthe lamp house are preferably made of sheet metal.

The source of light used with my apparatus is in the form of anincandescent electric lamp of the bulb type. As illustrated, said lamp26 is located in the lamp house 10 and between its opening 13 and theconcave reflector 22. In order to hold lamp 26 in position, the neck ofthe lamp socket 27 furnished with said bulb 26 is inserted in the openend of the sleeve 25 from the rear of the back plate 19 and theexternally screw threaded base of said lamp 26 is screwed into saidsocket from the concave side of the reflector 22. v a

In assembling such parts, the lamp 26 and its socket 27 are attached tothe reflector device 17 while the latter is removed from the lamp house10. After the incandescent bulb and its socket has been applied to thereflector, device 17, the latter is then inserted in the open rear endof the lamp house and occupies the position shown in Fig. 1. When it isdesired to renew a burnt out or otherwise disabled lamp, the reflectordevice 17 is withdrawn from the end of the lamp house and the disabledbulb removed and replaced by a new one.

In Fig. 1 of the drawings, I have shown the two vertically spaced reels28, 28 of the moving picture machine 14. About one reel is wound fromthe other the picture film 29. Said Fig. 1 also shows the two lenses 30,31 with which said machine is usually provided. Said lenses are locatedin front of the film 29 and as usually constructed, the outermost lens30 is secured in an upright position in a sleeve 32 which has endwise ortelescopic connection with the sleeve 33 in which the other lens 31 issecured. Said lenses are moved toward or from each other by anymechanism usually provided for that purpose, so as to regulate the focusof the image projected thereby on the screen. Asmy invention has nobearing on the moving picture projecting apparatus, I have therefore,shown and described only enough of such machine as to give a lucidunderstanding of the applicability of my light projecting apparatusthereto.

The concave reflector 22 is given such a curvature that the reflectedlight rays from the incandescent lamp 26 are projected outward towardand through the opening 13 in the conical hood 12 of the lamp house 10.

In other words, the curvature of the reflecting surface of the concavereflector 22 is such that the reflected light rays therefrom convergetoward the principal axis of the reflector 22 and tend to meet in acommon point situated beyond the front end of the lamp house. In short,the curvature of the reflecting surface of the concave reflector 22 issuch that the reflected light rays are concentrated on the rear lens 31,and by the aid of such lens, said light rays are brought to a focus at apoint between the lenses 30, 31 and on the principal axis thereof andbetween the forward lens 30 and its principal focus. By the aid of theforward lens 30 the image is projected on the screen right side up andenlarged. In Fig. 1, I have indicated by dotted lines 22, 22 the path ofseveral of the reflected light rays, and it will be noted that such raysconverge toward the principal axis of theconcave reflector 22 and areconcentrated on the rear lens 31.

Attached to the lamp socket 27 are inclosed conductor wires 34, 34 whichmay be connected with a suitable source of electric supply by means of awall socket in the lighting system.

In Fig. 3 ofthe drawings, I have shown, the lamp socket 27 adjustablymounted in the sleeve 25, so that when the incandescent bulb 26 issecured to the socket 27, the said lamp 26 may be adjusted toward oraway from the reflector 22 for the purpose of setting the source oflight in the proper position with respect to the curvature of thereflecting surface of the reflector 22 and thereby insure the reflectedlight rays being properly concentrated on the rear lens 31. Theadjusting means shown comprises a setscrew 35 inserted through thesleeve 25 to the rear of the back plate 19. The inner' end of theset-screw 35 is adapted to be impinged against the tubular neck of thelamp socket 27. The main advantage in providing the means whereby thebulb 26 may be adjusted with respect to the reflector 22 resides in thefact that, in case, the lead wires 36, 36 which support the metalfilament 37 in one lamp used are longer or shorter than in the lampwhich replaces the former, such variation in the length of lead wiresmay be compensated for by adjusting the lamp so as to bring the lightsource at the focus of the concave reflector 22.

In order to dissipate the excess heat, the lamp house 10 is providedwith a chimney and forward of the reflector 22. Said stack supportsabove the open upper end thereof a cowl 40. The back plate 19 isprovided with a plurality of apertures 41, 41 whereby air may circulatearound the back of the reflector 22 and thus serve to cool the same.

One of the main advantages arising in I the use of my apparatus residesin the fact that the source of light is in the form of an incandescentelectric lamp, which insures a constant and steady light stream soessential to moving picture and the like projecting machines.Furthermore, with an incandescent electric lamp as the source of light,there is no exposed light flame, such as present in electric arc lampsheretofore used. Consequently with an incandescent electric lamp.

there is no danger of fire in case the lamp bulb is fractured or brokenas the light source becomes immediately extinguished when the lamp bulbis broken. Moreover, my apparatus is inexpensive to manufacture andmaintain in use, when compared to the cost of an electric are lightequipment. Then again, my apparatus is portable and all parts thereofmay be assembled in the factory and the complete device readilyinstalled for use. Other and further advantages arising in use of mynovel apparatus will be readily apparent to those skilled in the art towhich my invention appertains.

Although, I have shown and described in detail herein one form in whicha light projecting apparatus embodying my invention may be made andconstructed, yet it is to be understood that I may variously modify andchange the details of construction and arrangement of parts shownwithout departing from the spirit and scope of my invention, and I donot want to be limited to the exact details of construction andarrangement shown, except as pointed out in the appended claim.

I claim as my invention:

A light projecting apparatus adapted for use with a cinematograph orother picture projecting device, comprising a lamp house having atubular body portion, a conical hood secured to one end of said bodyportion and having at its outer end an uncovered, lightemitting opening,a concave reflector completely closing the other end of said bodyportion, and an incandescent electric lamp located in said lamp houseand attached to said reflector.

In testimony that I claim the foregoing as my invention I aflix mysignature in the presence of two witnesses, this 2nd day of September,A. D. 1915.

FRANK A. HARDYMAN.

